The overall goal of these studies is to characterize immunologically- mediated adverse reactions to peanuts. Peanuts are among the three foods that account for over 80% of the food hypersensitivity reactions in children. In addition, peanut hypersensitivity usually persists into adulthood and is a lifelong diagnosis. The specific aims are: (1) to complete the production and sequence identification of recombinant peanut allergens, (2) to use these recombinant peanut allergens to characterize their B-cell allergenic determinants and determine if modifications in the peanut vicilin-like genes will produce proteins that result in a decreased immunologic response, and (3) to use these recombinant peanut allergens to characterize the T-cell allergenic determinants and the T-cell cytokine response, and to demonstrate that specific changes in the peanut vicilin- like genes will modify this immunologic reaction. Our previous investigations into IgE-mediated reactions to peanuts have identified three peanut allergens and characterized recombinant peanut allergens that share significant amino acid sequence homology with the vicilin family of seed storage proteins. An amino acid sequence comparison of the vicilins reveals that the primary difference between the large and small vicilin proteins is the existence of an additional tract of amino acids at the amino terminal end of the large vicilins. Our hypothesis is that the immunologic response to the seed storage proteins translated from the amino terminal end of the vicilin gene family is responsible for the unique hypersensitivity response to peanuts. Regional localization and then site-directed mutagenesis with immunoglobulin-binding and inhibition studies will be used to characterize the B-cell allergenic determinants. We will establish T-cell lines, clones, and precursor studies from our patient groups to characterize the T-cell determinants and the cytokine response, and to examine the regulatory mechanisms controlling IL-4 and interferon -gamma production. Further studies will alter specific B-cell and T-cell determinants to modify the immunologic response. The project addresses peanut allergy a significant health problem because of the potential severity of the allergic reaction, the chronicity of the allergic sensitivity, and the ubiquity of peanut products.